The game for the first half-hour was quite even with few chances for either team but the game turned on 33 minutes with a terrible decision from the officials handing Liverpool a penalty.
The referee initially gave a free kick until advised by his linesman the offence was inside the area.
The Black Cats and their manager Steve Bruce were incensed but up stepped Dirk Kuyt to convert from 12 yards.
This decision seemed to affect the home side who for all their efforts in the second half failed to trouble the Reds rearguard and were eventually punished with 13 minutes remaining.
Keeper Simon Mignolet seemed to get his angles all wrong as Luis Suarez fired home from tight against the by-line.
Sunderland’s miserable afternoon was complete when late on Mensah saw red after bringing down a goalbound Suarez.
Referee: Kevin Friend
Venue: Stadium of Light
03 Richardson (Malbranque 22)
05 Mensah (yellow card, red card)
19 Bramble (yellow card)
11 Muntari (Cattermole 19 (yellow card)
17 Welbeck (Elmohamady 60)
02 G Johnson
04 Meireles (Maxi 84)
21 Lucas (yellow card)
07 Suarez (yellow card) (Cole 89)
09 Carroll (Ngog 72)